Telephone answering devices are well known and widely used as consumer products. These devices include the ability to answer a telephone call, play a predetermined message, and record a message from the telephone caller. There are many other additional features which are available. Some devices allow messages to be played back over the telephone network via remote command from the caller. Additionally, other telephone answering devices have the capability to dial a predetermined telephone number and play back a recorded message to that telephone number. Other telephone answering devices use a prerecorded voice message to request the caller to enter data over the telephone by using a 12-button keypad. This data is then stored and forwarded to a paging type transmitter and ultimately received and displayed by a paging receiver.
None of these answering machines has been capable of selectively operating on a message based on the source of the call, with the source of the call being determined by an ANI signal generated by the telephone network. Although some answering devices are capable of selectively performing operations, they do so only at the prompt of the caller. Thus, the caller must enter additional information to identify himself or the steps he desires the answering device to perform. In this implementation, it is the caller who controls the operation of the answering device. The prior art shows no solution for executing a variety of predetermined operation based on the source of the call without caller intervention.
New paging receivers will be capable of recording and storing voice messages. The messages are sent to the pagers in an analog form, then digitized by the pager and stored in a Random Access Memory (RAM) contained within the pager. An example of such a device may be found in U.S. patent application Ser. No. 07/06,682 to Bennett, et al. entitled "Digitized Stored Voice Paging Receiver" and assigned to the assignee of the present invention, which is hereby incorporated by reference. In general, the amount of RAM required to store voice message is large compared to the amount of RAM normally required by paging devices. This RAM is costly and draws large amounts of current, thereby increasing the cost and reducing the battery life of a pager. Therefore, it is desirable to limit the amount of RAM required by the pager and further to limit its use, thereby reducing the cost and current drain of the pager. This can be done by selectively forwarding messages to the pager based upon a selection made by a telephone answering device and that selection is based upon the source of the telephone call.
The U.S. telephone network is evolving, and the evolution is to an integrated services digital network (ISDN) system. The ISDN system addresses the telecommunications issues of the future and will allow high speed computer-to-computer interfacing and voice message services over the telephone network as well as several other services, all on a standardized protocol. The aspects of the ISDN proposed systems are too broad to be addressed in this application, but one important aspect of the system is the automatic number identification (ANI) that will be included with each telephone message. The ISDN system already in place in several areas sends an ANI signal indicative of the telephone number of the origin of the telephone call. Thus, when the ISDN system is operational nationwide, it will be possible to determine the source of the telephone call prior to answering the telephone call. Currently, such ANI signals are commonly used in PBX systems and within the existing telephone network to route calls and handle billing charges. ANI signalling is also widely used in the "911" emergency telephone system. However, at this time, these ANI signals are generally not available at the receiving telephone call. Implementation of the full ISDN network will make these ANI signals generally available to the receiving telephone and/or telephone answering devices.